From: Andrew Morton <akpm@digeo.com>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: mremap() pte allocation atomicity error
Date: Fri, 27 Sep 2002 22:54:54 -0700 [thread overview]
Message-ID: <3D95442E.C0959F4A@digeo.com> (raw)
In-Reply-To: <20020928052813.GY22942@holomorphy.com>
William Lee Irwin III wrote:
>
> I'm working on something else atm.
>
> [<c01187b3>]__might_sleep+0x43/0x47
> [<c013b6d4>]__alloc_pages+0x24/0x20c
> [<c0133650>]file_read_actor+0x0/0x1b0
> [<c01131ed>]pte_alloc_one+0x41/0x104
> [<c012d05d>]pte_alloc_map+0x4d/0x210
> [<c013bc73>]get_page_cache_size+0xf/0x18
> [<c0135f38>]move_one_page+0xe8/0x328
> [<c0136061>]move_one_page+0x211/0x328
> [<c0130644>]vm_enough_memory+0x34/0xc0
> [<c01361a9>]move_page_tables+0x31/0x7c
> [<c0136860>]do_mremap+0x66c/0x7ec
> [<c0136a30>]sys_mremap+0x50/0x73
> [<c010748f>]syscall_call+0x7/0xb
>
ooh, oww, ouch. Look at move_one_page():
src = get_one_pte_map_nested(mm, old_addr);
if (src) {
dst = alloc_one_pte_map(mm, new_addr);
error = copy_one_pte(mm, src, dst);
get_one_pte_map_nested() does a kmap_atomic(), and then we go and
call alloc_one_pte_map->pte_alloc_map->pte_alloc_one->alloc_pages()
inside that kmap_atomic().
I guess that has been there since day one.
A simple fix would be to drop the atomic kmap of the source pte
and take it again after the alloc_one_pte_map() call.
Can you think of a more efficient way?
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next prev parent reply other threads:[~2002-09-28 5:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-28 5:28 William Lee Irwin III
2002-09-28 5:54 ` Andrew Morton [this message]
2002-09-28 6:04 ` William Lee Irwin III
2002-09-28 6:10 ` Andrew Morton
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